Embodiments of the present disclosure provide an Ethernet ring protection switching method, network device and system. In the embodiments of the present disclosure, a node obtains bandwidth information of a first link on an Ethernet ring on which the node is located, and determines that bandwidth of the first link changes, where there is at least one Ethernet ring protection instance on the Ethernet ring, and then the node determines ports of the node, where the at least one Ethernet ring protection instance passes through the ports, so that the node can query pre-configured correspondence between bandwidth information and switching information of each link on the Ethernet ring, and execute, through the ports of the node, a switching operation corresponding to the bandwidth information of the first link.